Arthroscopy is a particular form of endoscopy which, in turn, is the art of examining the interior of a body cavity or hollow organ by the use of a thin tubular instrument known as an "endoscope". Endoscopes have been in common use since the early 20th Century. These instruments include a lens system, which may be conventional glass lenses within a rigid tube, optical glass fibers, and a lighting system by which light from an external source is conducted through the optical glass fibers. Endoscopes also commonly contain an irrigation system for introducing fluids, typically normal saline solution, to the region being examined. Endoscopes have been used for arthroscopic examination for about fifteen years. The development of arthroscopy and instruments adapted for arthroscopic examinations, known specifically as arthroscopes, are described in an article entitled "Arthroscopy of the Knee" by Robert W. Jackson, et al., Modern Orthopedic Monographs, 1976, published by Brune & Stratton, Inc. of New York.
The arthroscope, like the endoscope, is a long tube with a fiber optic light carrier which permits light to be transmitted down the tube into the body, and which further permits the doctor to view the area of the body adjacent to the distal end of the arthroscope. Arthroscopes can be particularly useful in observing the conditions inside the human body. One area of the human body which arthoscopic viewing can be extremely useful is in the knee. A surgeon frequently finds it highly desirable to view the postermedial compartment of the knee in order to observe conditions in the compartment and to view the cartilage adjacent to the compartment.
Arthroscopy procedures have been performed in North America for the past fifteen years, and have been heralded by many physicians, professional athletes, managers and trainers as wonder surgery. Their reasoning is sound because arthroscopic surgery can usually be completed in about an hour in a doctor's office, the only anethesia required being local, and the recovery time being minimal, in many cases only a few weeks. The surgeon uses the arthroscope to perform this type of surgery. The instrument, which works on the same principle as a telescope, contains a tube with a fiber optic light carrier that lights up the joint, and glass lenses that reflect the image back to the surgeon. Some arthroscopes provide direct viewing, and others allow for 30.degree.-70.degree. angles.
In recent years, arthroscopic surgery of the knee joint has become a rapidly expanding procedure in the field of orthopedic surgery. Since the introduction of arthroscopy into the United States about fifteen years ago, arthroscopists have proliferated at a rapid rate.
Video systems for arthroscopy have recently been developed in which the eyepiece of the arthroscope is optically coupled to a video camera, and the arthroscopic images are displayed on the screen of a cathode-ray monitor. Such systems are marketed, for example, by Stryker Corporation of Kalamazoo, Mich. The present invention is concerned with arthroscopic video systems, and the principal objective of the invention is to provide an improved arthroscopic video system and assembly.
There also have been rapid advances in the state of the art with respect to arthroscopic equipment since its initial introduction and the recent use of the video camera and cathode-ray monitor have added significantly to the ease of arthroscopic use. The main problem insofar as video systems are concerned, however, is that the original arthroscope is still being used in the prior art systems, and it is coupled to the modern video camera through its original eyepiece by means of a cumbersome adapter. In order to keep the camera unit sterile, it is the usual present-day practice to use a plastic bag tied to the arthroscope with a piece of string. This makes it difficult to change the various arthroscope, for example, from a 10.degree. arthroscope to a 70.degree. arthroscope, without the danger of contamination. There is also the danger of water leaking into the camera unit and causing damage.
The assembly of the present invention includes an arthroscope which is constructed to be used with a video camera and, for that reason, does not have an eyepiece. The arthroscope in the assembly of the invention plugs into a mounting bracket which, in turn, plugs into a socket at one end of a tubular video camera housing using a bayonet-type of plug so that the arthroscope may be optically coupled to the video camera within the housing. The arthroscope is detachable from the mounting bracket, and it can be changed to any one of several arthroscopes having either direct viewing, or 10.degree.-30.degree.-70.degree. and even 90.degree. viewing angles, this being achieved within a matter of seconds, without any danger of contamination.
In the prior art systems, it was necessary to remove a plastic cover from the anthroscope before such a change could be made, and when that happened, the eyepiece of the arthroscope became contaminated, all of which created problems in the operating room.
The removable arthroscope used in the assembly of the present invention is compact and economical, since it does not have an eyepiece. An arthroscopic light is detachably attached to the mounting bracket. The removable arthroscope in the assembly of the invention is detached from the mounting bracket at a point displaced from the attachment of the arthroscopic light to the mounting bracket, so that when changing the arthroscope, the light source is not affected, and the electric cord supplying light to the arthroscopic light does not have to be detached, as is the case in the usual prior art assemblies.
The video camera housing in the assembly of the present invention encases the video camera in a sterile container which eliminates the need for the plastic bag. In practice, the housing is first sterlized in an autoclave, and is then opened at one end and the camera is inserted into the housing through the open end. The open end of the housing is then closed. The arthroscope is then plugged into the mounting bracket which, in turn, is plugged into the socket at the forward end of the housing by means of the bayonet plug. The electric cord for the video camera is attached to an electric socket at the rear end of the housing and the video camera is plugged into the socket. An advantage of the assembly of the invention is that it does not require a plastic cover sheet for the camera and cord. Also, the arthroscope can be changed to provide different lens angles without any danger of contamination.
The entire video monitor and cabinet in the prior art video arthroscope system is large and cumbersome, and takes up significant space in the operating room. There is also the problem of having multiple cables coming over from the video and light units which add to the complexity of the system. At present, it is usual to provide a large boom which holds the cables up over the operating table. A further objective of the present invention is to modify the overall system to make the assembly more compact.